A heat engine of a motor vehicle usually comprises cylinders delimiting combustion chambers in each of which is mounted a piston connected to an output shaft (or crankshaft) in order to apply a torque thereto. The output shaft is itself connected, via the gearbox, to wheels of the vehicle in order to rotate the latter. The output shaft is also connected to one or more auxiliary rotating machines such as the alternator in order to produce the electricity consumed onboard the vehicle.
There exist engines also comprising a member for managing a deactivation of one or more of the combustion chambers. Such engines with combustion chambers that can be deactivated usually comprise at least 8 combustion chambers. The deactivation of one or more combustion chambers makes it possible to limit fuel consumption when the engine load is constant. The deactivation of one or more combustion chambers however has the disadvantage of creating an imbalance of the output shaft that is likely to produce vibrations and relatively considerable operating noises. This imbalance is however less sensitive if the combustion chambers are numerous, so that the deactivation of the combustion chambers is used only in engines with large cubic capacity.
It is also a practice known from document U.S. Pat. No. 6,382,163 to reduce the imbalance during the deactivation phase itself, that is to say between the moments of deactivation and reactivation, by controlling a rotating machine such as an alternator starter coupled to the output shaft. However, the results obtained are not very satisfactory.